SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '845450ef58c98e0ac045c91b3814eda841693a7465d9e096a2638e81e20a9af2' 
  AND token = '33a3UQZLBNRS7c2tIhHean8QEvwa9Dn+cjtDB86N42o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}